It is an Arabic Qur'an free of all crookedness that they may - Surah Az-Zumar ayat 28 in English

﴿قُرۡءَانًا عَرَبِيًّا غَيۡرَ ذِي عِوَجٖ لَّعَلَّهُمۡ يَتَّقُونَ ﴾
[الزُّمَر: 28]

It is an Arabic Qur'an free of all crookedness that they may guard against their evil end

﴿قرآنا عربيا غير ذي عوج لعلهم يتقون﴾ [الزُّمَر: 28]

Abdel Haleem
an Arabic Quran, free from any distortion- so that people may be mindful

Abdul Hye
It is an Arabic Qur’an without any crookedness (flaw) in it in order that they may avoid all evil

Abdullah Yusuf Ali
(It is) a Qur'an in Arabic, without any crookedness (therein): in order that they may guard against Evil

Abdul Majid Daryabadi
An Arabic Qur'an, wherein there is no crookedness, that haply they may fear

Ahmed Ali
A clear discourse which expounds all things without any obliquity, so that they may take heed for themselves

Aisha Bewley
an Arabic Qur´an with no distortion in it, so that hopefully they will have taqwa

A. J. Arberry
Koran, wherein there is no crookedness; haply they will be godfearing

Ali Quli Qarai
—an Arabic Qur’an, without any deviousness, so that they may be Godwary